CN110621447B

CN110621447B - Robot conveyor calibration method, robot system and control system

Info

Publication number: CN110621447B
Application number: CN201780090669.6A
Authority: CN
Inventors: A·拉格; J·霍姆伯格; M·瓦尔斯特罗姆; M·斯滕巴卡
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2017-05-22
Filing date: 2017-05-22
Publication date: 2022-11-11
Anticipated expiration: 2037-05-22
Also published as: WO2018215047A1; EP3630417A1; US20200164518A1; US11511435B2; CN110621447A

Abstract

A conveyor coordinate system (X) for utilizing a movable conveyor member (18) _con ) To calibrate the robot coordinate system (X) of the robot (12) _base 、X _mi 、X _tool ) The method of (a), the method comprising: providing a sensor (24), the sensor (24) being configured to detect a position of the robot (12) in a non-contact manner; detecting a position of the robot (12) when the conveyor member (18) is positioned at the first operating position; detecting by the sensor (24) at a sensor coordinate system (X) when the conveyor member (18) is positioned at a second operative position different from the first operative position _sen ) A robot (12) and/or conveyor member (18) position; and based on the in-sensor coordinate system (X) _sen ) Detecting the position of at least one robot (12), determining a robot coordinate system (X) _base 、X _mi 、X _tool ) And transmitter coordinate system (X) _con ) The relationship between them. A robotic system (10) and a control system (16) are also provided.

Description

Robot conveyor calibration method, robot system and control system

Technical Field

The present disclosure generally relates to calibrating a robot coordinate system of a robot using a conveyor coordinate system of a movable conveyor member. In particular, a method for performing such calibration by using a non-contact sensor, a robot system for such calibration comprising a robot, a conveyor and a non-contact sensor, and a control system for such calibration are provided.

Background

Calibrating the robot to the conveyor can be a cumbersome and difficult operation, which is however also very important. For example, in pick and place robotic systems, the pick accuracy (i.e., the positioning accuracy of the robot when picking objects from a moving conveyor member of the conveyor) is well established depending entirely on the relationship between the position of the robot and the conveyor member.

The most common procedure used today for calibrating robots to conveyor components is to perform the calibration steps of the system manually. However, this process requires expertise (e.g., knowledge and experience) and is time consuming. Manual techniques are also required with good accuracy when the robot Tool Center Point (TCP) has to be jogged (jogged) to different reference points that are recorded with high precision.

US2017066133A1 discloses a coordinate system setting method configured to set a conveyor coordinate system having a predefined relationship with a base coordinate system of a robot as a coordinate system for defining a position of an object on a conveyor, having in a system an arrangement of: wherein the position of the object transferred by the conveyor is detected, and the robot performs work on the corresponding object based on the detected position. The method uses a plurality of features on a movable portion of the conveyor and a non-contact sensor provided on the robot.

WO0045229A1 discloses an apparatus and method for enabling an uncalibrated, model-independent controller for a mechanical system using a dynamic quasi-newtonian algorithm incorporating a velocity component of any moving system parameter.

WO2015121767A1 discloses an automatic calibration method for a robotic system, the method comprising: calibrating intrinsic parameters of the sensor and the sensor coordinate system; controlling the robot under the guidance of the calibrated sensor; and calculating a transformation matrix of the tool coordinate system relative to a tool center point coordinate system of the robot.

US2012229620A1 discloses an image processing apparatus including a management unit, an updating unit, an identifying unit, and a transmitting unit.

Disclosure of Invention

It is an object of the present disclosure to provide a method for calibrating a robot coordinate system of a robot using a conveyor coordinate system of a movable conveyor member, which method enables calibration to be simple, fast, automated and/or accurate.

It is a further object of the present disclosure to provide a robotic system configured to perform such calibration that addresses the above-mentioned objectives.

It is a further object of the present disclosure to provide a control system configured to control such calibration that addresses the above mentioned objectives.

According to one aspect, there is provided a method for calibrating a robot coordinate system of a robot using a conveyor coordinate system of a movable conveyor member. The method includes providing a sensor configured to detect a position of the robot in a non-contact manner; detecting, by the sensor, a position of the robot in a sensor coordinate system of the sensor when the conveyor member is positioned at the first operating position; detecting, by a sensor, a position of the robot and/or a position of the conveyor member in a sensor coordinate system when the conveyor member is positioned at a second operational position different from the first operational position; and determining a relationship between the robot coordinate system and the conveyor coordinate system based on the at least one detected position of the robot in the sensor coordinate system.

The conveyor member may be comprised by a conveyor. The conveyor member may be arranged to convey the object into (or within) the working range of the robot. As one example, the conveyor member may be constructed from a linear conveyor member (e.g., a conveyor belt). Alternatively, the conveyor member may be constituted by an endless conveyor member.

The conveyor member may be moved from the first position to the second position and vice versa. The conveyor member does not necessarily have to stop at the first and second operating positions. According to a variant, the conveyor member is continuously moved (e.g. at low speed) through the first and second operating positions. However, according to a variant, the conveyor member stops in one or both of the first and second operating positions. The robot may also be stationary or not when the same position is detected.

The sensor may be any type of sensor for detecting the position of the robot in a non-contact manner. For example, the sensor may be constituted by a visual sensor, such as: two-dimensional (2D) or three-dimensional (3D) vision sensors (e.g., cameras). The sensor may alternatively be formed by radar.

As used herein, a detected position may have translational components (e.g., x, y, and z offsets). Optionally, the detected position also has an orientation component (e.g., three euler angles) to indicate the orientation of the detected position (e.g., the orientation of the tool or marker).

By providing a sensor to detect the position of the robot in a non-contact manner, a simplified installation and a simplified removal of the sensor is made possible compared to attaching the sensor to the robot. For example, provision of a sensor configured to detect the position of the robot in a non-contact manner may include simply placing the sensor on a conveyor member or fixture structure (such as on a fixture portion of the conveyor or on a fixture structure on the floor). The simple installation and removal of the sensors helps to speed up the calibration process of the robotic system and reduce down time of the robotic system.

In the case where the sensor is positioned on the fixture structure (e.g., outside of the conveyor member), the sensor may remain at this position during operation of the robotic system. Thus, after stopping the operation of the robot system, a further calibration process may be started quickly.

The robot may include a tool, and the position of the robot may be a position of the tool. For industrial robots, the position of the tool in the robot coordinate system is basically known. However, the position of the robot may be any position that can be identified by the sensors and has a known or calculable position in the robot coordinate system. For example, markers may be attached to the robot to define the position of the robot to be detected by the sensor.

The method may further comprise: the position of the robot in the different poses is detected in the sensor coordinate system by the sensor when the conveyor member is in the first operating position and/or when the conveyor member is in the second operating position. For example, the sensor may detect two poses of the robot when the conveyor member is positioned at the first operative position, and the sensor may detect one pose of the robot when the conveyor member is positioned at the second operative position. In this situation, the robot may move from the first pose to the second pose before the conveyor member moves from the first operative position to the second operative position. As a further example, the sensor may only detect a first pose of the robot when the conveyor member is positioned at the first operative position, and the sensor may only detect a second pose of the robot when the conveyor member is positioned at the second operative position.

The sensor may be positioned on the conveyor member, and the method may include: the position of the robot is detected in the sensor coordinate system by the sensor when the conveyor member is positioned at the first operating position and when the conveyor member is positioned at the second operating position. For example, the sensor may simply be placed on or secured to the conveyor member (e.g., by using a clamp). In this case, the step of determining the relationship between the robot coordinate system and the conveyor coordinate system may be based on two positions of the robot detected in the sensor coordinate system (i.e. in the first operating position of the conveyor member and the second operating position of the conveyor member).

The method may further comprise: determining a direction of movement of the conveyor member in the robot coordinate system based on the detected position of the robot in the sensor coordinate system; and determining a relationship between the robot coordinate system and the conveyor coordinate system based on the determined direction of movement of the conveyor member. For example, if the sensor is positioned on a linear conveyor member and the conveyor member is moved from a first operative position to a second operative position, the movement of the sensor may be defined by a vector that is parallel to the direction of movement of the conveyor member. If the conveyor member is constituted by an endless conveyor member, the direction of movement of the conveyor member may be determined based on the position of the robot detected in three different operating positions of the conveyor member. The direction of movement of the conveyor member may first be determined in the sensor coordinate system and then in the robot coordinate system.

The method may be used to calibrate a plurality of robots along a conveyor member. In this case, the method may further include: moving the conveyor member from the second operative position to a third operative position; detecting, by the sensor, a position of the second robot in the sensor coordinate system when the conveyor member is positioned at the third operating position; moving the conveyor member from the third operating position to a fourth operating position; detecting, by the sensor, a position of the second robot in the sensor coordinate system when the conveyor member is positioned at the fourth operating position; and determining a relationship between the robot coordinate system and the conveyor coordinate system of the second robot based on the position of the second robot detected in the sensor coordinate system (i.e. based on the at least one position of the second robot when the conveyor member is positioned at the third operating position and based on the at least one position of the second robot when the conveyor member is positioned at the fourth operating position). The third operating position may be downstream of the second operating position, and the fourth operating position may be downstream of the third operating position, as seen in the direction of movement of the conveyor member.

The relationship between the sensor coordinate system and the transmitter coordinate system may be known in advance. Alternatively, it may be detected or set, for example, during calibration. This may be useful when the position of the conveyor member is not registered by the sensor (e.g. when the sensor is arranged to face only the robot).

The sensor may be further configured to detect the position of the conveyor member in a non-contact manner. Thus, the sensor may be positioned on the conveyor member to face both the robot and the conveyor member. In this situation: the sensor may detect a position of the robot when the conveyor member is positioned at the first operating position; the sensor may detect a position of the robot when the conveyor member is positioned at the second operating position; and the sensor may detect the position of the conveyor member when the conveyor member is positioned at the first operative position, the second operative position, or at any other operative position.

The method may further comprise: detecting, by a sensor, a position of a conveyor member in a sensor coordinate system; and determining a relationship between the sensor coordinate system and the conveyor coordinate system based on the detected position of the conveyor member in the sensor coordinate system.

At least one calibration mark may be provided on the conveyor component, which calibration mark is used for detection of the position of the conveyor component. The position of the at least one calibration mark in the conveyor coordinate system may be known in advance. Alternatively, it may be detected or set during, for example, calibration.

The sensor may be positioned on the mount structure so that the conveyor member moves relative to the sensor, and the sensor may be further configured to detect the position of the conveyor member in a non-contact manner. Thus, the sensor may be positioned on the fixture structure to face both the robot and the conveyor member. In such a situation, the step of determining the relationship between the robot coordinate system and the conveyor coordinate system may be based on only one position of the robot detected in the sensor coordinate system (i.e. when the conveyor member is positioned at the first operating position, the second operating position, or at any other operating position).

The fixing structure may be constituted, for example, by a fixing part of the conveyor or by a fixing structure on the floor, such as a shelf or table, on which the sensor is positioned. The fixture structure according to the present disclosure may also be constituted by a mobile device which is kept stationary when the calibration method is performed. At least one calibration mark may be provided on the conveyor component, which calibration mark is used for detection of the position of the conveyor component.

The method may further comprise: detecting, by a sensor, a position of at least one calibration mark in a sensor coordinate system when the conveyor member is positioned at the first operating position; detecting, by the sensor, a position of the at least one calibration mark in the sensor coordinate system when the conveyor member is positioned at the second operating position; determining a direction of movement of the conveyor member in the robot coordinate system based on the position of the at least one calibration mark detected in the sensor coordinate system; and determining a relationship between the robot coordinate system and the conveyor coordinate system based on the determined direction of movement of the conveyor member. The position of the at least one calibration mark in the conveyor coordinate system may be known in advance. Alternatively, it may be detected or set during, for example, calibration.

If the conveyor member is constituted by a linear conveyor member, the direction of movement of the conveyor member may be determined based on the position of the at least one calibration mark detected in two different operating positions of the conveyor member. If the conveyor member is constituted by an endless conveyor member, the direction of movement of the conveyor member may be determined on the basis of the position of the at least one calibration mark detected in three different operating positions of the conveyor member.

According to a further aspect, there is provided a robotic system comprising: at least one robot, a movable conveyor member, and a sensor configured to detect a position of the robot in a non-contact manner. The robotic system may be configured to perform any method according to the present disclosure. A robotic system may include a plurality of robots working along a conveyor member (e.g., by picking up objects). One or more robots, conveyor members, and sensors of a robotic system may be of any type in accordance with the present disclosure.

According to a further aspect, there is provided a control system for calibrating a robot coordinate system of a robot using a conveyor coordinate system of a movable conveyor member in a robot system, the robot system comprising: a robot, a conveyor member, and a sensor configured to detect a position of the robot in a non-contact manner, the control system comprising: a data processing apparatus and a memory, the memory having stored thereon a computer program comprising program code which, when executed by the data processing apparatus, causes the data processing apparatus to perform the steps of: controlling the sensor to detect a position of the robot in a sensor coordinate system of the sensor when the conveyor member is positioned at the first operating position; controlling the sensor to detect a position of the robot and/or the conveyor member in a sensor coordinate system when the conveyor member is positioned at a second operational position different from the first operational position; and determining a relationship between the robot coordinate system and the conveyor coordinate system based on the detected at least one position of the robot in the sensor coordinate system. The control system thus provides for an automatic and contactless calibration method.

Drawings

Further details, advantages and aspects of the disclosure will become apparent from the following examples taken in conjunction with the accompanying drawings, in which

Fig. 1a schematically shows a perspective view of a robotic system according to a first embodiment, wherein the conveyor member is positioned at a first operative position;

FIG. 1b schematically illustrates a perspective view of the robotic system in FIG. 1a, but with the conveyor member positioned at a second operative position;

figure 2a schematically shows a perspective view of the robotic system according to a second embodiment, wherein the conveyor member is positioned at a first operative position;

FIG. 2b schematically shows a perspective view of the robotic system in FIG. 2a, but with the conveyor member positioned at a second operating position;

fig. 3 schematically shows a perspective view of a further robot system according to the first embodiment;

fig. 4 schematically shows a perspective view of a further robot system according to a second embodiment;

fig. 5a schematically shows a perspective view of a robot system according to a third embodiment, wherein the conveyor member is positioned at a first operating position; and

fig. 5b schematically shows a perspective view of the robotic system in fig. 5a, but with the conveyor member positioned at the second operating position.

Detailed Description

Hereinafter, a robot-conveyor calibration method using a non-contact sensor, a robot system including a robot, a conveyor, and a non-contact sensor for this calibration, and a control system for this calibration will be described. The same reference numerals will be used to designate the same or similar structural features.

Fig. 1a and 1b schematically show perspective views of a robot system 10 according to a first embodiment. The robot system 10 includes: a robot 12, a conveyor 14, and a control system 16.

Conveyor 14 includes a movable conveyor member 18, here exemplified as a conveyor belt. In operation of the robotic system 10, the conveyor members 18 convey objects (not shown) in a direction of movement 20 into a work area of the robot 12, wherein one or more objects are handled by the robot 12. One example of a processing operation that may be performed by the robot 12 is a pick operation. The robot 12 may thus pick up the object from the conveyor members 18 and place the object at a placement location (not shown). Even though the robot 12 is illustrated as an articulated robot, the robot 12 may be of any type. As one example, the robot 12 may alternatively be powered by

And (4) robot construction.

The robot 12 illustrated in fig. 1a comprises three robot coordinate systems: base coordinate system X _base Tool coordinate system X _tool And a mounting interface coordinate system X _mi . Base coordinate system X _base Is a cartesian coordinate system with its origin at the base of the robot 12. Tool coordinate system X _tool Is a cartesian coordinate system with its origin at the tool 22 of the robot 12 (here exemplified as a vacuum gripper with a single suction cup). Mounting interface coordinate system X _mi Is its originA cartesian coordinate system at the mounting interface of the tool 22. According to the present disclosure, the base coordinate system X of the robot 12 _base Tool coordinate system X _tool Mounting interface coordinate system X _mi Or any other coordinate system may be used as the robot coordinate system of robot 12, which is used for the conveyor coordinate system X with the conveyor members 18 _con And (6) calibrating. Transmitter coordinate system X _con Is also a cartesian coordinate system and has its origin on the conveyor member 18.

When the robot 12 performs a treatment operation on one or more objects, it is important that the robot coordinate system X of the robot 12 _base 、X _mi 、X _tool And the transmitter coordinate system X of the transmitter member 18 _con Is well calibrated. With good calibration, the defined positions in the conveyor coordinate system (such as the position of an object on the conveyor member 18) can be in the robot coordinate system X _base 、X _mi 、X _tool Is accurately defined. Thus, the precision of the treatment operations performed by the robot 12 on the objects on the conveyor members 18 may be improved, wherein in turn the robot 12 is enabled to perform more complex and/or faster tasks. As a further result, the risk of failure of the robotic system 10 may be reduced.

The robotic system 10 also includes sensors 24. The sensor 24 is a non-contact sensor and may for example be constituted by a 2D or 3D vision sensor (e.g. a camera). Cartesian sensor coordinate system X _sen Is associated with the sensor 24.

The sensor 24 of the first embodiment is positioned on the conveyor member 18. As can be seen in fig. 1a, the sensor 24 is oriented vertically upwards. Thus, the sensor 24 is configured to detect the position of the robot 12 in a non-contact manner. Position detection may be accomplished by any known measurement technique. In fig. 1a, the sensor 24 is configured to detect the position of the tool 22 of the robot 12 as the position of the robot 12.

According to a first embodiment, for using the transmitter coordinate system X _con To calibrate the robot coordinate system X _base 、X _mi 、X _tool Will now be described. First, the sensor 24 is placed on the conveyor member 18 facing the robot 12. In fig. 1a, conveyor member 18 is positioned in a first operating position. When conveyor member 18 is positioned at the first operating position, sensor 24 detects a position in sensor coordinate system X _sen Of the tool 22. In other words, the transformation between the tool 22 and the sensor 24 is measured. When the conveyor member 18 is positioned at the first operating position, the position of the tool 22 is detected for at least one pose of the robot 12.

Then, as illustrated in fig. 1b, the conveyor member 18 (and the sensor 24 thereon) is moved in the moving direction 20 from the first operating position to the second operating position. When conveyor member 18 is positioned at the second operating position, sensor 24 detects that tool 22 is in sensor coordinate system X _sen To a further position in (a). For this detection, the robot 12 may be the same pose as in fig. 1a, or may be a different pose. In the example of fig. 1a and 1b, the robot 12 remains in the same pose when the conveyor member 18 is positioned at the first operative position and at the second operative position.

From the data collected by sensors 24, the direction of movement 20 of conveyor member 18 may be determined, but the relationship between robot 12 and conveyor member 18 cannot be determined. The relative position of the sensor 24 in space can be used to find the direction of movement 20. Two points of the sensor 24 in space may be used to construct a vector from which the direction of movement 20 may be determined.

For example, the motion vector may be in the robot coordinate system X _tool Is calculated and expressed as follows. The robot 12 is caused to have the same posture for the first operation position and the second operation position. The measured position of tool 22 at the first operative position of conveyor member 18 is inverted. This will give the sensor 24 the robot coordinate system X _tool To the first position. The measured position of tool 22 at the second operative position of conveyor member 18 is inverted. This will give the sensor 24 translated in the robot coordinate system X _tool Of (c) is used. Subtracting the two positions to obtain the coordinate system X of the robot _tool The motion vector expressed in (1).

The transformation between sensor 24 and transmitter member 18 may be known in advance in order to obtain the final transformation between sensor 24 and transmitter member 18. Alternatively, it may be detected or set during, for example, calibration. Once calibration is complete, the sensors 24 may be removed from the conveyor members 18 and the robotic system 10 is ready for operation.

By using the calibration method according to the first embodiment, all calibration steps can be automated and the calibration accuracy will be high without relying on manual or professional techniques. It is also easier to simply place the sensor 24 on the conveyor member 18 than to mount the sensor 24 on the tool 22 of the robot 12.

For calibration, the conveyor member 18 may be moved to a further operating position for detecting a further position of the robot 12 by the sensor 24. At each operating position of conveyor member 18, sensor 24 may detect more than one position of robot 12 (e.g., different poses of robot 12). If several poses of the robot 12 are detected at one operational position of the conveyor member 18, then from the mounting interface coordinate system X _mi Tool coordinate system X _tool May be calculated as an additional result.

From the installation interface coordinate system X _mi Tool coordinate system X _tool May not always be known. The tool 22 is essentially customized for the application that the robot 12 is to execute (e.g., pick up cheese). Size of tool 22 and position (X) of tool 22 _tool ) Will be different for different user scenarios. However, the size of the robot 12 (including the position X of the mounting interface) _mi ) Are basically known beforehand.

However, the position (X) of the tool 22 may be found by having the sensor 24 for multiple (e.g., at least two) different poses of the robot 12 _tool ) Thereby finding the transformation. Since the pose of the robot 12 is known, andthe mounting interface coordinate system X from the tool 22 using the data found by the sensor 24 _mi Tool coordinate system X _tool May be calculated. From the installation interface coordinate system X _mi Tool coordinate system X _tool Transformation X of _mt Can be calculated as follows.

Wherein X _tooli Is X _tool Position of the ith measurement, X _toolj Is X _tool Position of the j-th measurement, X _mii Is an installation interface X _mi Ith position of (2), X _mij Is an installation interface X _mi And i and j are positive integers.

Control system 16 controls sensor 24 and transmitter member 18. In this example, the control system 16 also controls the robot 12. Control system 16 is configured to control sensors 24, conveyor members 18, and robot 12 to perform the calibration method as described herein.

The control system 16 includes a data processing device 26 (e.g., a central processing unit, CPU) and a memory 28. The computer program is stored in the memory 28. In a first embodiment, the computer program may comprise program code which, when executed by the data processing apparatus 26, causes the data processing apparatus 26 to: controlling sensor 24 to detect that robot 12 is in sensor coordinate system X of sensor 24 when conveyor member 18 is positioned at the first operating position _sen The position of (1); controlling movement of conveyor member 18 from the first operative position to the second operative position; controlling sensor 24 to detect that robot 12 is in sensor coordinate system X when conveyor member 18 is positioned at the second operating position _sen The position of (1); and based on the in-sensor coordinate system X _sen The detected position of the robot 12 is determined in the robot coordinate system X _base 、X _mi 、X _tool And transmitter coordinate system X _con The relationship between them. In accordance with the present disclosure, the computer program may also include computer code,wherein the data processing device 26, when executed by the data processing device 26, is caused to control the conveyor members 18, the sensors 24, and the robot 12 (and possibly other robots) according to the present disclosure. Control system 16 is in signal communication with conveyor member 18, sensors 24, and robot 12 (and possibly other robots).

Fig. 2a and 2b schematically show perspective views of a robot system 10 according to a second embodiment. The main differences with respect to the first embodiment will be described.

The sensor 24 of the second embodiment is also positioned on the conveyor member 18. As can be seen in fig. 2a, the sensor 24 is angled slightly upwards with respect to the horizontal and faces both the conveyor member 18 and the robot 12. Accordingly, sensor 24 is configured to detect the position of robot 12 and to detect the position of conveyor member 18.

Calibration marks 30 are provided on conveyor component 18. Sensor 24 can thus detect that conveyor member 18 is in sensor coordinate system X _sen Of (c) is used. Calibration marks 30 may be any type of feature on conveyor component 18 that is identifiable by sensor 24. Calibration marks 30 may be provided permanently on conveyor component 18 (e.g., painted marks) or may be provided temporarily on conveyor component 18 (e.g., attached pyramids).

According to a second embodiment, the transmitter coordinate system X is used _con To calibrate the robot coordinate system X _base 、X _mi 、X _tool Will now be described. Sensor 24 is first placed on conveyor member 18, facing both conveyor member 18 and robot 12. In fig. 2a, conveyor member 18 is positioned in a first operating position. When conveyor member 18 is positioned at the first operating position, sensor 24 is in sensor coordinate system X _sen The position of the detection tool 22 and the position of the calibration marks 30. In other words, the transformation between the tool 22 and the sensor 24 and the transformation between the calibration marks 30 and the sensor 24 are measured. From these transformations, a transformation between the calibration mark 30 and the tool 22 can be found. When the conveyor component18 are positioned at the first operating position, the position of the tool 22 is detected for at least one pose of the robot 12.

Then, as illustrated in fig. 2b, the conveyor member 18 (and the sensor 24 thereon) is moved in the moving direction 20 from the first operating position to the second operating position. When conveyor member 18 is positioned at the second operative position, sensor 24 is in sensor coordinate system X _sen Detects a further position of the tool 22. For this detection, the robot 12 may be in the same pose as in fig. 2a, or may be in a different pose. Sensor 24 may alternatively detect the position of calibration marks 30 when conveyor member 18 is in the second operating position or any other operating position.

The direction of movement 20 may be determined as described above by data from the tool 22 collected by the sensor 24. In the transmitter coordinate system X _con The position of the calibration marks 30 in (a) may be known in advance to obtain the final transformation between the tool 22 and the conveyor member 18. Alternatively, it may be detected or set during, for example, calibration.

By using the calibration method according to the second embodiment, all calibration steps can be automated and the calibration accuracy will be high without relying on manual or professional techniques. It is also easier to simply place the sensor 24 on the conveyor member 18 than to mount the sensor 24 on the tool 22 of the robot 12.

Fig. 3 schematically shows a perspective view of a further robot system 10 according to a first embodiment, and fig. 4 schematically shows a perspective view of a further robot system 10 according to a second embodiment. Referring collectively to fig. 3 and 4, the robotic system 10 includes two robots, a first robot 12 and a second robot 32.

Each of the calibration methods of the variations of the first and second embodiments in fig. 3 and 4 includes: moving conveyor member 18 from the second operative position to the third operative position; when the conveyor member is positioned at the third operative position, in the sensor coordinate system X by the sensor 24 _sen Detects the position of the second robot 32; moving conveyor member 18 from the third operative position to the fourth operative position; when the conveyor member is positioned at the fourth operative position, in the sensor coordinate system X by the sensor 24 _sen Detects the position of the second robot 32; and based on the in-sensor coordinate system X _sen The detected position of the second robot 32 is detected, and the robot coordinate system X of the second robot 32 is determined _base 、X _mi 、X _tool And transmitter coordinate system X _con The relationship between them. Fig. 3 illustrates the conveyor member 18 in a second operating position, and fig. 4 illustrates the conveyor member 18 in a third operating position.

Thus, with the variation in fig. 3 and 4, several robots along the same conveyor member 18 can be calibrated by moving only the conveyor member 18 with the sensor 24 forward to the next robot 32 after the calibration of the previous robot 12. This calibration process is very simple and fast.

Fig. 5a and 5b schematically show perspective views of a robot system 10 according to a third embodiment. The main differences corresponding to the first and second embodiments will be described.

The sensor 24 of the third embodiment is positioned on a mount structure 34. In the example of fig. 5a, the fixture structure 34 is implemented as a shelf on the floor. As can be seen in fig. 5a, the sensor 24 is facing both the robot 12 and the conveyor member 18 so that the calibration marks 30 thereon can be seen. Accordingly, the sensor 24 is configured to detect the position of the robot 12 and to detect the position of the conveyor member 18. The fixture structure 34 may alternatively be attached to a wall or may be constructed from the fixture portion of the transmitter 14.

According to a third embodiment, the transmitter coordinate system X is used _con To calibrate the robot coordinate system X _base 、X _mi 、X _tool Will now be described. Sensor 24 is placed on the outside of conveyor member 18, facing both the upper layers of conveyor member 18 and robot 12. In FIG. 5a, conveyor member 18 is positioned atIn the first operating position. When transmitter member 18 is positioned at the first operative position, sensor 24 is in sensor coordinate system X _sen The position of the detection tool 22 and the position of the calibration marks 30. In other words, the shift between the tool 22 and the sensor 24 and the shift between the calibration mark 30 and the sensor 24 are measured. From these transformations, a transformation between the calibration mark 30 and the tool 22 can be found. When the conveyor member 18 is positioned at the first operating position, the position of the tool 22 is detected for at least one pose of the robot 12.

Then, illustrated in fig. 5b, the conveyor member 18 (instead of the sensor 24) is moved in the moving direction 20 from the first operating position to the second operating position. When conveyor member 18 is positioned at the second operating position, sensor 24 is in sensor coordinate system X _sen Detecting a further position of the calibration mark 30.

From the data of the calibration marks 30 collected by the sensor 24, the direction of movement 20 can be determined. The relative position in space of the calibration marks 30 is used to find the direction of movement 20. For example, the motion vector may be in the robot coordinate system X _base 、X _mi 、X _tool Is calculated and expressed as follows. Calibration mark 30 is in sensor coordinate system X _sen Is subtracted to obtain the position in the sensor coordinate system X _sen The motion vector of (1). Since the robot 12 is in the (now fixed) sensor coordinate system X _sen Has been measured, so the motion vector can be derived from the sensor coordinate system X _sen Is transformed to the robot coordinate system X _base 、X _mi 、X _tool . Alignment marks 30 in the conveyor coordinate system X _con May be known in advance to obtain the final transformation between tool 22 and conveyor member 18. Alternatively, it may be detected or set during, for example, calibration.

Sensor 24 may alternatively or additionally detect the position of tool 22 when conveyor member 18 is positioned at the second operating position, or any other operating position. For this detection, the robot 12 may be either in the same pose as in fig. 5a, or in a different pose.

By using the calibration method according to the third embodiment, all calibration steps can be automated and the calibration accuracy will be high without relying on manual or professional techniques. The third embodiment also has the advantage that the sensor 24 can be placed in any suitable location where it can "see" both the conveyor member 18 and the robot 12.

While the present disclosure has been described with reference to exemplary embodiments, it should be appreciated that the invention is not limited to what has been described above. For example, it should be appreciated that the dimensions of the parts may be varied as desired. Accordingly, the invention is intended to be limited only by the scope of the appended claims.

Claims

1. A conveyor coordinate system (X) using a movable conveyor member (18) _con ) To calibrate the robot coordinate system (X) of the robot (12) _base 、X _mi 、X _tool ) The method of (1), the method comprising:

providing a sensor (24), the sensor (24) being configured to detect a position of the robot (12) in a non-contact manner;

when the conveyor member (18) is positioned at a first operating position, a sensor coordinate system (X) at the sensor (24) by the sensor (24) _sen ) Detecting a position of the robot (12);

by the sensor (24) in the sensor coordinate system (X) when the conveyor member (18) is positioned at a second operative position different from the first operative position _sen ) Detecting a position of the robot (12) and/or the conveyor member (18); and

based on the robot (12) in the sensor coordinate system (X) _sen ) Determines the robot coordinate system (X) _base 、X _mi 、X _tool ) And said transmitter coordinate system (X) _con ) The relationship between them.

2. The method of claim 1, wherein the robot (12) includes a tool (22), and wherein the position of the robot (12) is a position of the tool (22).

3. The method according to claim 1 or 2, wherein the method further comprises: by the sensor (24) in the sensor coordinate system (X) when the conveyor member (18) is in the first operative position, and/or when the conveyor member (18) is in the second operative position _sen ) Detecting the position of the robot (12) in different poses.

4. The method of claim 1 or 2, wherein the sensor (24) is positioned on the conveyor member (18), and wherein the method comprises: when the conveyor member (18) is positioned at the first operative position, and when the conveyor member (18) is positioned at the second operative position, by the sensor (24) in the sensor coordinate system (X) _sen ) Detecting a position of the robot (12).

5. The method of claim 4, wherein the method further comprises:

based on the robot (12) in the sensor coordinate system (X) _sen ) Is determined in the robot coordinate system (X) _base 、X _mi 、X _tool ) A direction of movement (20) of the conveyor member (18); and

determining the robot coordinate system (X) based on the determined movement direction (20) of the conveyor member (18) _base 、X _mi 、X _tool ) With the transmitter coordinate system (X) _con ) The relationship between them.

6. The method of claim 4, wherein the robot (12) constitutes a first robot (12), and wherein the method further comprises:

moving the conveyor member (18) from the second operative position to a third operative position;

when the conveyor member (18) is positioned at the third operative position, by the sensor (24) in the sensor coordinate system (X) _sen ) Detecting a position of the second robot (32);

moving the conveyor member (18) from the third operative position to a fourth operative position;

when the transmitter member (18) is positioned at the fourth operative position, passing the sensor (24) in the sensor coordinate system (X) _sen ) Detecting a position of the second robot (32); and

based on the second robot (32) in the sensor coordinate system (X) _sen ) Determines a robot coordinate system (X) of the second robot (32) _base 、X _mi 、X _tool ) And said transmitter coordinate system (X) _con ) The relationship between them.

7. The method of claim 4, wherein the sensor coordinate system (X) _sen ) With the transmitter coordinate system (X) _con ) The relationship between them is known in advance.

8. The method of claim 4, wherein the sensor (24) is further configured to detect the position of the conveyor member (18) in a non-contact manner.

9. The method of claim 8, wherein the method further comprises:

by the sensor (24) in the sensor coordinate system (X) _sen ) Detecting a position of the conveyor member (18); and

based on the transmitter member (18) in the sensor coordinate system (X) _sen ) Determining the sensor coordinate system (X) _sen ) And said transmitter coordinate system (X) _con ) The relationship between them.

10. The method of claim 1 or 2, wherein the sensor (24) is positioned on a fixture structure (34) such that the conveyor member (18) moves relative to the sensor (24), and wherein the sensor (24) is further configured to detect the position of the conveyor member (18) in a non-contact manner.

11. Method according to claim 9, wherein at least one calibration mark (30) is provided on the conveyor member (18) for detection of the position of the conveyor member (18).

12. The method of claim 10, wherein at least one calibration mark (30) is provided on the conveyor member (18) for detection of the position of the conveyor member (18), and the method further comprises:

when the conveyor member (18) is positioned at the first operative position, passing the sensor (24) in the sensor coordinate system (X) _sen ) Detecting the position of the at least one calibration mark (30);

when the conveyor member (18) is positioned at the second operative position, by the sensor (24) in the sensor coordinate system (X) _sen ) Detecting a position of the at least one calibration mark (30);

based on the at least one calibration mark (30) in the sensor coordinate system (X) _sen ) Is determined in the robot coordinate system (X) _base 、X _mi 、X _tool ) A direction of movement (20) of the conveyor member (18); and

determining the robot coordinate system (X) based on the determined movement direction (20) of the conveyor member (18) _base 、X _mi 、X _tool ) And said transmitter coordinate system (X) _con ) The relationship between them.

13. Method according to claim 11, wherein in the transmitter coordinate system (X) _con ) The above-mentionedThe position of at least one calibration mark (30) is known in advance.

14. A robotic system (10), comprising: at least one robot (12, 32), a movable conveyor member (18) and a sensor (24), the sensor (24) being configured to detect a position of the robot (12, 32) in a non-contact manner, wherein the robotic system (10) is configured to perform the method according to any of the preceding claims.

15. A control system (16) for utilizing a conveyor coordinate system (X) of a movable conveyor member (18) in a robotic system (10) _con ) To calibrate the robot coordinate system (X) of the robot (12) _base 、X _mi 、X _tool ) The robot system includes: the robot (12), the conveyor member (18) and a sensor (24), the sensor (24) being configured to detect a position of the robot (12) in a non-contact manner, the control system (16) comprising a data processing device (26) and a memory (28) having stored thereon a computer program comprising program code, wherein the program code, when executed by the data processing device (26), causes the data processing device (26) to perform the steps of:

controlling the sensor (24) to detect a sensor coordinate system (X) at the sensor (24) when the conveyor member (18) is positioned at a first operative position _sen ) The position of the robot (12);

controlling the sensor (24) to detect in the sensor coordinate system (X) when the conveyor member (18) is positioned at a second operating position different from the first operating position _sen ) A position of the robot (12) and/or a position of the conveyor member (18); and

based on the robot (12) in the sensor coordinate system (X) _sen ) Determining the robot coordinate system (X) from the detected at least one position _base 、X _mi 、X _tool ) And withSaid transmitter coordinate system (X) _con ) The relationship between them.